• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.7.1-7.1
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• 2011

Nanoporous templates have been widely used for the development of new functional nanostructured materials suitable for electronics, optics, magnetism, and energy storage materials. We have prepared nanoporous templates by using thin films of mixtures of polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) and PMMA homopolymers. These templates have cylindrical nanoholes spanning the entire thickness of the film. Some applications of nanoporous templates are introduced: a) anti-reflective coating, b) the preparation of conducting polymer nanowires of poly (pyrrole), poly (3,4-ethylenedioxy-thiopene) onto a glass coated with indium-tin-oxide, and c) the separation membranes for biomaterials. We found that when the pore fraction of nanoholes in the film was ~0.68, almost zero reflectance at a specific wavelength, which can be changed with film thickness, was achieved at visible wavelengths Furthermore, ultra high density array of conducting nanowires was successfully prepared onto various substrates including flexible polymer. Due to highly alignment of polymer chain along the nanowire direction, the conductivity was much increased. Furthermore, these nanoporous films were found to be very effective for the separation of human Rhinovirus type 14 (HRV 14), major pathogen of a common cold in humans, from the buffer solution. We also found that when the pore size was effectively controlled down to 6 nm, a single file diffusion was observed.

• 폴리머
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• 제38권2호
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• pp.188-192
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• 2014

본 연구에서는 용해도가 낮은 용매에 dipping하는 방법을 이용하여 고분자 반도체 박막의 분자규칙도를 쉽게 향상시켰다. Poly(3-hexylthiophene)(P3HT)의 구조적, 광학적, 전기적 특성은 dipping 용매의 용해도와 dipping 시간에 따라 크게 영향을 받았다. 특히 methylene chloride 용매에 P3HT 박막을 dipping한 뒤 dipping 시간을 조절하여 고분자 박막의 분자규칙도를 효과적으로 증가시켰다. 분자규칙도와 전기적 특성의 관계를 고려하여 적절한 용매선택과 dipping 시간을 최적화할 수 있었다.

• 한국레이저가공학회지
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• 제13권1호
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• pp.11-15
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• 2010

Indium tin oxide (ITO) provides high electrical conductivity and transparency in the visible and near IR (infrared) wavelengths. Thus, it is widely used as a transparent electrode for the fabrication of liquid crystal displays (LCDs) and organic light emitting diode displays (OLRDs), photovoltaic devices, and other optical applications. Lasers have been used for removing coating on polymer substrate for flexible display and electronic industry. In selective removal of ITO layer, laser wavelength, pulse energy, scan speed, and the repetition rate of pulses determine conditions, which are efficient for removal of ITO coating without affecting properties of the polymer substrate. ITO coating removal with a laser is more environmentally friendly than other conventional etching methods. In this paper, pattering of ITO film from polymer substrates is described. The Yb:KGW femtosecond laser processing system with a pulse duration of 250fs, a wavelength of 1030nm and a repetition rate of 100kHz was used for removing ITO coating in air. We can remove the ITO coating using a scanner system with various pulse energies and scan speeds. We observed that the amount of debris is minimal through an optical and a confocal microscope, and femtosecond laser pulses with 1030nm wavelength are effective to remove ITO coating without the polymer substrate ablation.

• 멤브레인
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• 제25권2호
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• pp.171-179
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• 2015

과불소계 술폰화 이오노머(perfluorinated sulfonic acid ionomers; PFSAs)는 뛰어난 수소이온전도성과 높은 내화학성으로 인해 고분자 전해질 연료전지(polymer electrolyte fuel cells)용 고체전해질로 널리 사용되고 있다. 그러나 PFSA 전해질은 가습-건조조건에서 연료전지가 구동에 따라 반복적인 팽윤-수축으로 인해 전극층이 전해질로부터 탈리되어 전기화학적 수명특성이 감소되는 문제점을 가지고 있다. 본 연구에서는 다공성 PTFE support film의 기공특성에 대한 이해를 바탕으로 기공구조 내 나피온 이오노머를 함침시키는 강화막을 제조하였고, 기본특성을 평가하였다. 제조된 강화막은 매우 높은 수소이온전도도(${\sim}~0.5S\;cm^{-1}@90^{\circ}C$ in liquid water)를 나타내었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.55-59
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• 2009

The epoxy resin without hardener can harden by a ring-opening reaction in the presence of the alkalies produced by the hydration of cement in epoxy-modified mortars and concretes. This paper investigates the effect of curing conditions on the strength improvement of polymer-modified mortars using bisphenol A-type epoxy resin without hardener. The polymer-modified mortars using epoxy resin are prepared with various polymer-cement ratios, and subjected to ideal, water, dry and heat cures. In the heat cure, the epoxy-modified mortars are sealed or unsealed with a PVDC (polyvinylidene chloride) film. The epoxy-modified mortars are tested for flexural and compressive strengths at desired curing methods. The microstructures of the epoxy-modified mortars are also observed by scanning electron microscope. The effects of curing conditions on the strength development of the epoxy-modified mortars are examined. From the test results, the marked effectiveness of the heat cure under the PVDC film sealing against the development of the strength of the epoxy-modified mortar without the hardener is recognized. The flexural and compressive strengths of 7-day-90℃ heat-cured, PVDC film-sealed epoxy-modified mortars without hardener reach 7 to 17MPa and 24 to 44MPa respectively, and are two to three times of Unmodified mortar. Such high strength development of the epoxy-modified mortars may be achieved by the dense microstructure formation by cement hydrates and the hardening of the epoxy resin in the mortars.

• Bulletin of the Korean Chemical Society
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• 제28권6호
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• pp.1015-1020
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• 2007

A simple approach to prepare arrays of Au/TiO2 composite nanoparticles by using Au-loaded block copolymers as templates combined with a sol-gel process is described. The organic-inorganic hybrid films with closely packed inorganic nanodomains in organic matrix are produced by spin coating the mixtures of polystyrene-block-poly(ethylene oxide) (PS-b-PEO)/HAuCl4 solution and sol-gel precursor solution. After removal of the organic matrix with deep UV irradiation, arrays of Au/TiO2 composite nanoparticles with different compositions or particle sizes can be easily produced. Different photoluminescence (PL) emission spectra from an organic-inorganic hybrid film and arrays of Au/TiO2 composite nanoparticles indicate that TiO2 and Au components exist as separate state in the initial hybrid film and form composite nanoparticles after the removal of the block copolymer matrix.

• 한국정밀공학회지
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• 제22권6호
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• pp.144-151
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• 2005

Spin coater is regarded as a major module rotating at high speed to be used build up polymer resin thin film layer fur bonding process of GaAs wafer. This module is consisted of spin unit for spreading uniformly, align device, resin spreading nozzle and et. al. Specially, spin unit which is a component of module can cause to vibrate and finally affect to the uniformity of polymer resin film layer. For the stability prediction of rotation velocity and uniformity of polymer resin film layer, it is very important to understand the dynamic characteristics of assembled spin coater module and the dynamic response mode resulted from rotation behavior of spin chuck. In this paper, stress concentration mode and the deformed shape of spin chuck generated due to angular acceleration process are presented using analytical method for evaluation of structural safety according to the revolution speed variation of spin unit. And also, deformation form of GaAs wafer due to dynamic behavior of spin chuck is presented fur the comparison of former simulated results.

• 폴리머
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• 제26권6호
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• pp.778-784
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• 2002

덱스트란 용액으로 필름을 제조하여 여러 가지 특성들을 살펴보았으며, 가소제 및 가교제를 첨가하거나 저온 플라스마로 표면을 처리함으로써 이러한 특성들을 향상시킬 수 있는 지를 살펴보았다. 덱스트란 필름은 기계적 강도는 우수하였으나 부스러지기 쉽고 수분에 대단히 약한 특성을 보였다 가소제를 첨가할 경우에는 유연성이 크게 개선되는 대신에 기계적 강도가 크게 약화되었다. 하지만, 가소제를 첨가한 다음 가교제로 가교시키거나 함께 첨가할 경우에는 비교적 우수한 기계적 강도와 함께 유연성을 지닌 필름이 제조되었으며, 수분에 대한 저항성도 향상되었다. 또한, 아세틸렌 플라스마로 처리할 경우 필름 자체의 특성은 크게 변하지 않으나 친수성인 표면이 소수성으로 바뀌었다.

• 공업화학
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• 제35권3호
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• pp.209-213
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• 2024

전도성 페이스트와 PET 필름 사이의 접착특성 개선을 위해 PET 필름을 산과 염기를 이용하여 화학 처리와 코로나 방전처리를 통한 물리적 처리를 진행하였다. 실제 산업적 제조에 적용되는 에틸셀룰로오스와 실란 처리 셀룰로오스 나노섬유(cellulose nano fiber, CNF)를 바인더로 적용한 페이스트를 제조하고 PET 필름에 코팅하여 접착특성을 비교하였다. 코로나 방전 처리된 PET 필름에 실란 처리 CNF가 바인더로 적용된 페이스트가 코팅된 시편에서 접착특성이 최고 수준인 5B를 나타내었다. 반면, PET 필름을 산/염기로 화학처리한 경우 접착특성 개선 효과가 나타나지 않음을 확인할 수 있었다.

• KIEE International Transactions on Electrophysics and Applications
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• 제2C권6호
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• pp.281-286
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• 2002

The temperature accelerated dielectric breakdown strength of on-wafer low-k dielectric polymer films with thicknesses ranging from 94 nm to 1141 nm is investigated by using the current-voltage characteristic measurements with MIS structures. The temperature dependence of dielectric strength is demonstrated to be Arrhenious for all thicknesses. However, the activation energy is found to be strongly thickness dependent. It follows an exponential relationship rather than being a single value, i.e., the activation energy increase significantly as film thickness increases for the thickness below 500 nm, but it is almost constant for the thickness above 500 nm. This relationship suggests that the change of the activation energy corresponding to different film thickness is closely related to the temperature dependence of the electron trapping/detrapping process in polymer thin films, and is determined by both the trapping rate and the detrapping rate. Thinner films need less energy to form a conduction path compared to thicker films. Hence, it leads to smaller activation energy in thinner films, and the activation energy increases with the increase in film thickness. However, a nearly constant value of the activation energy is achieved above a certain range of film thickness, indicating that the trapping rate and detrapping rate is almost equal and eventually the activation energy approaches the value of bulk material.